After turning impossible to possible with his 18th Grand Slam title at the age of 35, ending a four-and-a-half year wait, Roger Federer seemed to accept he may already be contemplating retirement.

Roger Federer took his record number of Grand Slam singles titles to 18 after a classic five-set final victory over Spain’s Rafael Nadal in the Australian Open final on Sunday. (REUTERS)

Roger Federer completed an improbable comeback from injury at 35 to end a four-and-a-half year wait for a record-extending 18th Grand Slam title on Sunday, and then hinted that retirement can’t be far away. (Australian Open final highlights).

The Swiss maestro became the oldest Grand Slam champion in the Open Era after Ken Rosewall, who won the Australian Open title in 1972 aged 37, following his 6-4 3-6 6-1 3-6 6-3 triumph on the Rod Laver Arena in Melbourne.

Accepting the winner’s trophy, Federer, the winner of the most number of Grand Slam titles and five at Melbourne Park, suggested it can’t get any better than the classic five-setter he produced with Spaniard Rafael Nadal.

“Tennis is a tough sport, there are no draws in tennis but I would have been happy to accept one tonight and share it with Rafa,” Federer said, paying tribute his biggest opponent. Nadal still leads 6-3 in Grand Slam finals.

“I would have been happy to lose to be honest, the comeback was as good as it was,” he told the Melbourne Park audience, and millions of fans watching on TV, before adding: “I hope to see you next year, but if not, then it was a wonderful year here and I couldn’t be happier tonight.”

As Federer’s Grand Slam title drought extended since his last at the 2012 Wimbledon, he was irritated whenever the question came up at tournament press conferences.

At last, the man regarded as arguably the greatest tennis player ever, seems to be at peace with that thought.